1. Field of the Invention
The invention relates to a method for hot forging at least one end of a steel reinforcing bar (commonly referred to as a rebar), or the like, so as to form an enlarged threaded head during a single step. The threaded head of the rebar is adapted to be connected to an opposing threaded rebar by means of a suitable threaded coupler to be used, for example, to reinforce a precast concrete structure.
2. Background Art
From time-to-time, it becomes necessary to connect one steel bar to another. By way of example, in the case of concrete construction or repair, a plurality of steel reinforcing bars are connected end-to-end to be embedded within a precast concrete structure to enhance the strength of the structure and enable the structure to avoid shifting relative to an adjacent structure and better withstand the effects of an earthquake and other natural forces. Opposite ends of a pair of axially-aligned rebars are connected together by means of a coupler located therebetween. In this case, the opposing ends of the rebars to be connected together are threaded during a cold working process by either rolling or cutting the threads into the bars. The threaded ends of the rebars are rotated into mating engagement with a correspondingly threaded coupler. To maximize the cross-sectional (i.e., tensile) property of the bars, the threaded end of each can be enlarged prior to threading by either one of an independent cold or hot forming or forging step. In this case, the bar is provided with a relatively wide upset head often known in the art as a button or mushroom head.
It would be desirable to combine the advantages of upsetting and threading one or both ends of a rebar or the like during an efficient one-step process so as to eliminate the need to perform the separate and time-consuming independent steps in the manner described above.